/*
 * $Id$
 *
 * Copyright 2009 Sun Microsystems, Inc., 4150 Network Circle,
 * Santa Clara, California 95054, U.S.A. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */
package org.jdesktop.swingx.plaf.basic.core;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import javax.swing.Action;
import javax.swing.ActionMap;
import javax.swing.JComponent;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.plaf.ActionMapUIResource;

/**
 * An ActionMap that populates its contents as necessary. The contents are
 * populated by invoking the <code>loadActionMap</code> method on the passed in
 * Object.
 *
 * @version 1.6, 11/17/05
 * @author Scott Violet
 */
public class LazyActionMap extends ActionMapUIResource {
	/**
	 * Object to invoke <code>loadActionMap</code> on. This may be a Class
	 * object.
	 */
	private transient Object _loader;

	/**
	 * Installs an ActionMap that will be populated by invoking the
	 * <code>loadActionMap</code> method on the specified Class when necessary.
	 * <p>
	 * This should be used if the ActionMap can be shared.
	 *
	 * @param c
	 *            JComponent to install the ActionMap on.
	 * @param loaderClass
	 *            Class object that gets loadActionMap invoked on.
	 * @param defaultsKey
	 *            Key to use to defaults table to check for existing map and
	 *            what resulting Map will be registered on.
	 */
	public static void installLazyActionMap(JComponent c, Class loaderClass, String defaultsKey) {
		ActionMap map = (ActionMap) UIManager.get(defaultsKey);
		if (map == null) {
			map = new LazyActionMap(loaderClass);
			UIManager.getLookAndFeelDefaults().put(defaultsKey, map);
		}
		SwingUtilities.replaceUIActionMap(c, map);
	}

	/**
	 * Returns an ActionMap that will be populated by invoking the
	 * <code>loadActionMap</code> method on the specified Class when necessary.
	 * <p>
	 * This should be used if the ActionMap can be shared.
	 *
	 * @param c
	 *            JComponent to install the ActionMap on.
	 * @param loaderClass
	 *            Class object that gets loadActionMap invoked on.
	 * @param defaultsKey
	 *            Key to use to defaults table to check for existing map and
	 *            what resulting Map will be registered on.
	 */
	static ActionMap getActionMap(Class loaderClass, String defaultsKey) {
		ActionMap map = (ActionMap) UIManager.get(defaultsKey);
		if (map == null) {
			map = new LazyActionMap(loaderClass);
			UIManager.getLookAndFeelDefaults().put(defaultsKey, map);
		}
		return map;
	}

	private LazyActionMap(Class loader) {
		_loader = loader;
	}

	public void put(Action action) {
		put(action.getValue(Action.NAME), action);
	}

	public void put(Object key, Action action) {
		loadIfNecessary();
		super.put(key, action);
	}

	public Action get(Object key) {
		loadIfNecessary();
		return super.get(key);
	}

	public void remove(Object key) {
		loadIfNecessary();
		super.remove(key);
	}

	public void clear() {
		loadIfNecessary();
		super.clear();
	}

	public Object[] keys() {
		loadIfNecessary();
		return super.keys();
	}

	public int size() {
		loadIfNecessary();
		return super.size();
	}

	public Object[] allKeys() {
		loadIfNecessary();
		return super.allKeys();
	}

	public void setParent(ActionMap map) {
		loadIfNecessary();
		super.setParent(map);
	}

	private void loadIfNecessary() {
		if (_loader != null) {
			Object loader = _loader;

			_loader = null;
			Class klass = (Class) loader;
			try {
				Method method = klass.getDeclaredMethod("loadActionMap", new Class[] { LazyActionMap.class });
				method.invoke(klass, new Object[] { this });
			} catch (NoSuchMethodException nsme) {
				assert false : "LazyActionMap unable to load actions " + klass;
			} catch (IllegalAccessException iae) {
				assert false : "LazyActionMap unable to load actions " + iae;
			} catch (InvocationTargetException ite) {
				assert false : "LazyActionMap unable to load actions " + ite;
			} catch (IllegalArgumentException iae) {
				assert false : "LazyActionMap unable to load actions " + iae;
			}
		}
	}
}
